She was last seen by family members when she went to bed at 11 p.m. on a Friday. When her father went to wake her at 8 a.m. Saturday -- a half-hour after her mother had gone to work -- he said the girl was nowhere to be found, according to police.

Police have followed 2,200 leads in the case, which attracted national attention.

No arrests have been announced and the chief would not discuss suspects at a news conference.

The chief said Isabel's remains were found in a rural part of Pima County, which includes Tucson.

DNA from the remains was sent to a lab in Virginia, he said.

"Unfortunately the results of this DNA analysis did confirm that the remains were those of Isabel Celis," Magnus said.

The chief said the discovery was not happenstance but he declined to say what led officers to the site.

KGUN said the girl's family released this statement: "We want to thank the community for the support they have continued to show for Isa over the years and for refusing to give up hope. Now is our time to mourn. We ask for our privacy during this time so that we can do that."